Waterproof & Breathability Rating Instruction
Waterproof and breathability ratings are used to measure the ability of a fabric to keep water out and allow moisture to escape. Waterproof ratings are typically expressed in millimeters (mm), with a higher number indicating a higher level of water resistance. Breathability ratings are typically expressed in grams (g), with a higher number indicating a higher level of breathability.
To understand how waterproof and breathability ratings work, it's helpful to know a little bit about the science behind these ratings. Waterproof fabrics are typically coated with a waterproof layer, such as a polymer or wax, that prevents water from penetrating the fabric. Breathable fabrics, on the other hand, are designed to allow moisture to escape from the inside of the fabric.
When a fabric is tested for its waterproof and breathability ratings, it is typically done using a standardized test called the Hydrostatic Head Test and the Moisture Vapor Transmission Rate (MVTR) Test. The Hydrostatic Head Test measures the pressure at which water begins to penetrate the fabric, while the MVTR Test measures the amount of moisture that can pass through the fabric in a given amount of time.
The results of these tests are then used to assign a waterproof rating and a breathability rating to the fabric. For example, a fabric with a waterproof rating of 10,000 mm and a breathability rating of 10,000 g would be considered very waterproof and highly breathable.
In general, the higher the waterproof and breathability ratings, the more effective a fabric will be at keeping you dry and comfortable in wet and rainy conditions. However, it's important to note that these ratings are not always directly comparable across different brands and fabrics, as different testing methods may be used. It's always a good idea to read the care instructions and product descriptions carefully to understand the specific ratings and performance of a particular fabric.
